A. Field of the Invention
The present invention relates generally to valves and more particularly to a valve for use in a mud pump.
B. Description of the Prior Art
During the drilling of oil and gas wells, drilling fluids are circulated within the bore hole by means of positive displacement pumps commonly called mud pumps. The inlet and the outlet ports of mud pumps are provided with poppet-type valves, which include a seat ring and a valve disc adapted for reciprocal motion with respect to the seat ring. Typically, the valve disc also includes an elastomer insert or seal ring fitted into a groove around the periphery of the valve disc. In order to accommodate and carry the seal ring, the valve disc is typically a relatively large and massive structure.
The seal ring engages a relatively steeply tapered frusto-conical surface on the seat ring when the valve is in the closed position. The steep taper of the sealing surface of the seat ring requires that the valve disc be lifted a relatively large distance in order to open the valve to allow mud flow. The combination of the high lift and large mass of the valve disc results in substantial inertia as the valve disc travels back and forthb etween the open and closed positions. The high inertia makes the valve operate relatively sluggishly and results in slamming of the valve to the closed position, which increases wear on the valve parts.